"Green" plastics-Will Polylactic Acid emerge as a viable choice?

The dominance of synthetic plastics derived from fossil fuels in to day's world is scary as petroleum sources are not going to last for ever and the question as to what then is driving the scientific community feverishly to innovate and come up with viable alternatives based on renewable sources. While cellulose based plastics are manufactured and used for a variety of applications, their functional properties do not come any where near that of synthetic plastics. An yet another problem associated with petroleum based plastics is their near indestructibility and their biodegradability credentials. It takes almost 800 years for most plastics to degrade in nature and disposal in land fills posses enormous dangers to the safety of the environment including water resources. Emergence of poly lactic acid based plastics was thought to be an answer to this problem. Unfortunately these biodegradable plastics cost too high to be commercially viable. The major factor in this cost escalation is the manufacturing technology which appears to be too complex and expensive. Recently a group of scientists from Belgium have come up with a new approach for producing cheaper poly lactic acid base material which if true can be a ground breaking development Read further below.    

"The bioplastic PLA is derived from renewable resources, including the sugar in maize and sugarcane. Fermentation turns thesugar into lactic acid, which in turn is a building block for polylactic acid. PLA degrades after a number of years in certain environments. If it is collected and sorted correctly, it is both industrially compostable and recyclable. In addition, PLA is biocompatible and thus suitable for medical use, for instance in absorbable suture threads. PLA is also one of the few plastics that are suitable for 3D printing. However, polylactic acid is not yet a full alternative for petroleum-based plastics due to its cost. The production process for PLA is expensive because of the intermediary steps. "First, lactic acid is fed into a reactor and converted into a type of pre-plastic under high temperature and in a vacuum. This is an expensive process. The pre-plastic – a low-quality plastic – is then broken down into building blocks for polylactic acid. In other words, you are first producing an inferior plastic before you end up with a high-quality plastic. And even though PLA is considered a green plastic, the various intermediary steps in the production process still require metals and produce waste," said Prof Bert Sels from the Centre for Surface Chemistry and Catalysis. The KU Leuven researchers developed a new technique. Michiel Dusselier, a postdoctoral researcher, explained, "We have applied a petrochemical concept to biomass. We speed up and guide the chemical process in the reactor with a zeolite as a catalyst. Zeolites are porous minerals. By selecting a specific type on the basis of its pore shape, we were able to convert lactic acid directly into the building blocks for PLA without making the larger by-products that do not fit into the zeolite pores. Our new method has several advantages compared to the traditional technique: we produce more polylactic acid with less waste and without using metals. In addition, the production process is cheaper, because we can skip a step."

Whether this development can lead to large scale production of the new plastic materials remains to be seen. At least there is a hope that an alternative option is available on the table. Of course lactic acid production from biomass materials through intervention of microbes can still pose a logistical problem because of competition from fuel industry which also is working on fermentation route for making green fuel. Already there is some criticism regarding diversion of food materials like corn, plant oils and other organic carbon sources for production of alcohol and other fuels to replace fossil fuels. World has to take a holistic view of this critical area and only cooperative endeavors can succeed ultimately.  

V.H.POTTY
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POLYSTYRENE FOAM CONTAINERS-A LITTER HAZARD?

Recent reports that the ever progressive state of California in the US is about to ban the use of polystyrene plastic is a welcome news for many environmentalists and enlightened citizens, knowing well about the darker side of this fossil fuel based product. While expanded polystyrene is extensively used for packing foods or as disposable containers, extruded polystyrene is the most popular insulation material being a bad conductor of heat. Being made from petroleum chemicals its safety for food contact applications is questionable while it has very poor biodegradability credentials. It is worth emulating the US in abolishing polystyrene which has many natural alternatives.

"Expanded polystyrene foam, commonly known as Styrofoam, is a lightweight plastic that, when littered, is often carried from streets through storm drains into the ocean. It accounts for 15% of storm drain litter, according to the California Department of Transportation. It is the second-most-common type of beach debris, according to a study by the Southern California Coastal Water Quality Research Project. Fifty California jurisdictions have already banned foam takeout food packaging, including Huntington Beach, Santa Monica, Malibu and Ventura County. "There are all these jurisdictions in California that have to control trash and reduce their discharges of trash to waterways, and they're having a hard time complying because foam litter is so hard to control. That's the reason for this bill," said Miriam Gordon, state director of Clean Water Action, a national advocacy group that sponsored SB 568".

One is justified in getting scared using polystyrene, especially for food contact applications, considering that it is suspected to be linked to neural damage and cancer. It is unfortunate that millions of people who use polystyrene disposable cups and plates are totally unaware of the dangers lurking behind this plastic material. Take out dinners and frozen meals are invariably packed in polystyrene containers, ready for nuking in microwave oven and how much "leachate" emerges at higher temperatures is still not certain. Polystyrene, like any other plastics, can be recycled but the needed facilities are far and few.

V.H.POTTY
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BIOPLASTICS-THE NEW "SURGE"

Production of plastics is estimated at about 270 million tons (mt) per year world-wide and most of it originated from petroleum resources. The huge quantity of non-biodegradable plastics generated year after year due to limited recycling practices is posing an enormous challenge in disposing them of, after use. Bio-plastics are being touted as the answer to the hydrocarbon based plastics of to day. Of course, it certainly is not a panacea but if the world is compelled to move to a fossil fuel free state, some alternative options should be available to make plastics on which the modern society depends so heavily. If the studies by scientists from Utrecht University are any indication, Bio-plastics will definitely be a potential option in the years to come.

"In their study, Martin K. Patel, Li Shen and Juliane Haufe demonstrate that up to 90 percent of the current global consumption of polymers can technically be converted from oil and gas to renewable raw materials." But while that's a pretty huge number, this is a theoretical ceiling. In the short to mid-term, the numbers are much lower: "Based on recent company announcements the production capacity of bio-based plastics is projected to increase from 360,000 tons in 2007 to about 2.3 million tons by 2013." The production of Bio-plastics could grow by on average 37 percent annually until 2013. Ceresana Research predicts the largest growth rates in electronics and auto industries. The Freedonia Group, an industrial research company, sees demand growing fastest in the Asia-Pacific region, and some predict the U.S. market to reach $10 billion a year by 2020, a tenfold increase from 2007.

Probably world will be left with no choice but to use Bio-plastics, once the fossil fuels start dwindling and their cost starts climbing steeply. Most eligible candidates in the Bio-plastic group would be Starch based plastics, poly lactic acid (PLA) and Bio-based Polyethylene (PE) and Polyhydroxy Alkanoates (PHA). World has to go a long way before bio-plastics production can assume a dominant role for industrial use.

V.H.POTTY

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